I understand what kind of compressor you are getting now and it is a specialty type designed to deliver cool dry air at the expense of performance, it however is not very well suited to body work. I am surprised that you can run a collision shop on just 12 CFM but if that is the case then what you are doing will work and if you don't mind a 45 minute recharge time then I guess what you want to do is OK, I just think there are much more efficient and definitely cheaper ways of accomplishing the the same thing. A good two stage compressor of around 16 to 18 CFM and an 80 gallon tank would be cheaper and air supply would never be a problem, it is arguable that it might not be as dry as what that Curtis might deliver but do you really need instrument quality air? If you are using a good two stage of the capabilities I used as an example and your air demand is only going to be around 12 CFM or less as you mentioned then the two stage will deliver very cool air and a simple water separator and proper plumbing will provide air more than dry enough for most body work. Still, you know what kind of air quality you are looking for and so I assume that you have a reason and if so that Curtis should deliver and if that extremely long recharge time is worth a couple of extra minutes of run time then it should work like you are thinking.